After a process exits, all ports linked to it from other processes
should be closed. All unsent file descriptors in port queue, marked as
"close after send", should be closed to avoid resource leakage.
According to the C standard, pointer arguments passed to memcpy() calls shall
still have valid values. NULL is considered as invalid.
Found with GCC Static Analyzer.
This is useful to escape "/" in path fragments. For example, in order
to reference the application named "foo/bar":
{
"pass": "applications/foo%2Fbar"
}
This is required due to lack of a graceful shutdown: there is a small gap
between the runtime's memory pool release and router process's exit. Thus, a
worker thread may start processing a request between these two operations,
which may result in an http fields hash access and subsequent crash.
To simplify issue reproduction, it makes sense to add a 2 sec sleep before
exit() in nxt_runtime_exit().
After 41331471eee7 completion handlers should complete next buffer in chain.
Otherwise buffer memory may leak.
Thanks to Peter Tkatchenko for reporing the issue and testing fixes.
An earlier attempt (ad6265786871) to resolve this condition on the
router's side added a new issue: the app could get a request before
acquiring a port.
One of the ways to detect Unit's startup and subsequent readiness to accept
commands relies on waiting for the control socket file to be created.
Earlier, it was unreliable due to a race condition between the client's
connect() and the daemon's listen() calls after the socket's bind() call.
Now, unix domain listening sockets are created with a nxt_listen_socket_create()
call as follows:
s = socket();
unlink("path/to/socket.tmp")
bind(s, "path/to/socket.tmp");
listen(s);
rename("path/to/socket.tmp", "path/to/socket");
This eliminates a time-lapse when the socket file is already created but nobody
is listening on it yet, which therefore prevents the condition described above.
Also, it allows reliably detecting whether the socket is being used or simply
wasn't cleaned after the daemon stopped abruptly. A successful connection to
the socket file means the daemon has been started; otherwise, the file can be
overwritten.
The "return" action can be used to immediately generate a simple HTTP response
with an arbitrary status:
{
"action": {
"return": 404
}
}
This is especially useful for denying access to specific resources.
To avoid closing the body fd prematurely, the fd value is moved from
the request struct to the app link. The body fd should not be closed
immediately after the request is sent to the application due to possible
request rescheduling.
If kqueue reported both the EVFILT_READ and the EVFILT_WRITE events
for the socket but only the former had the EV_EOF flag set, the flag
was silently ignored.
It allows proceeding to another action if a file isn't available.
An example:
{
"share": "/data/www/",
"fallback": {
"pass": "applications/php"
}
}
In the example above, an attempt is made first to serve a request with
a file from the "/data/www/" directory. If there's no such file, the
request is passed to the "php" application.
Fallback actions may be nested:
{
"share": "/data/www/",
"fallback": {
"share": "/data/cache/",
"fallback": {
"proxy": "http://127.0.0.1:9000"
}
}
}
